Panels comprising a mechanical locking device and an assembled product comprising the panels

ABSTRACT

A set of panels including a first panel with a first main plane and a second panel with a second main plane. The first and the second panel are provided with a mechanical locking device for locking a first edge of the first panel to a second edge of the second panel at a junction plane, wherein the first main plane is essentially perpendicular to the second main plane and the junction plane is extending between the first main plane and the second main plane. The first edge includes an edge tongue that extends from the junction plane. The second edge includes an edge groove at the junction plane. The edge tongue is configured to cooperate with the edge groove for locking together the first and the second edges in a first direction which is perpendicular to the first main plane. The edge tongue includes a tongue groove.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of Swedish Application No.1650089-4, filed on Jan. 26, 2016. The entire contents of SwedishApplication No. 1650089-4 are hereby incorporated herein by reference intheir entirety.

TECHNICAL FIELD

Embodiments of the present invention relates to panels that may bearranged perpendicular to each other and locked together with amechanical locking device. The panels may be assembled and lockedtogether to obtain a furniture product, such as a bookshelf, a cupboard,a wardrobe, a box, a drawer or a furniture component. The locking devicemay comprise a flexible tongue.

BACKGROUND

A furniture product provided with a mechanical locking device is knownin the art, as evidenced by WO2015/038059. The furniture comprises afirst panel connected perpendicular to a second panel by a mechanicallocking device comprising a flexible tongue in an insertion groove.

SUMMARY

One object of certain embodiments of the present invention to provide animprovement over the above described technique and the known art. Aspecific objective is to improve assembling of panels, such as furniturepanels, locked together by a mechanical locking device and/or toincrease the strength of the mechanical locking device. The panels maybe a part of a furniture product, such as a furniture component, adrawer, a cupboard, a bookshelf, a wardrobe, a kitchen fixture, or abox.

At least some of these and other objects and advantages that will beapparent from the description have been achieved by a first aspect ofthe invention that includes a set of panels comprising a first panelwith a first main plane and a second panel with a second main plane. Thefirst and the second panel are provided with a mechanical locking devicefor locking a first edge of the first panel to a second edge of thesecond panel at a junction plane. The first main plane is essentiallyperpendicular to the second main plane and the junction plane isextending between the first main plane and the second main plane. Thefirst edge comprises an edge tongue that extends from the junctionplane. The second edge comprises an edge groove at the junction plane.The edge tongue is configured to cooperate with the edge groove forlocking together the first and the second edges in a first directionwhich is perpendicular to the first main plane. The edge tonguecomprises a tongue groove. The edge groove comprises a flexible tonguearranged in an insertion groove. Said flexible tongue is configured tocooperate with the tongue groove for locking together the first and thesecond edges in a second direction which is perpendicular to the secondmain plane. The mechanical locking device comprises a first space,between the edge tongue and the edge groove, at an opening of the edgegroove and at the junction plane, in a locked position of the first andthe second edge. The first space may have the advantage that a loadingof a part of the second edge at the opening of the edge groove isavoided. This part of the second edge may be a weak part, since littlematerial is available to absorb a load.

The angle between the junction plane and the first main plane may be ina range of about 30° to about 60°, for example about 45°.

The edge tongue may extend, from the junction plane, essentially in thesecond direction, and preferably with a longitudinal direction along thefirst edge.

A first side of the edge tongue may comprise, at the junction plane, afirst locking surface. The edge groove, at the junction plane, maycomprise a second locking surface. The first locking surface and thesecond locking surface may be essentially parallel and may be configuredto cooperate for locking in the first direction. The first lockingsurface and the second locking surface are preferably extendingessentially in the second direction.

The edge tongue, at a second side, which is opposite the first side, maycomprise a third locking surface and the edge groove may comprise afourth locking surface. The third locking surface and the fourth lockingsurface may be essentially parallel and may be configured to cooperate,at a distance from the junction plane, for locking in the firstdirection. The third locking surface and the fourth locking surface arepreferably extending essentially in the second direction.

The third locking surface and the fourth king surface may cooperate atan area, extending in the second, direction, over a first distance. Thethird locking surface and the fourth locking surface may be displacedfrom the junction plane by a second distance. The first distance may bewithin the range of about 20% to about 200% of the second distance,preferably within the range of about 50% to about 150% of the seconddistance. The first distance may be essentially the same as the seconddistance.

The first side of the edge tongue, at a distance from the junctionplane, may comprise a fifth locking surface and the edge groove maycomprise a sixth locking surface at a distance from the junction plane.The fifth locking surface and the sixth locking surface may beessentially parallel and may be configured to cooperate for locking inthe first direction. The fifth locking surface and the sixth lockingsurface are preferably extending essentially in the second direction.

The mechanical locking device may comprise a first contact surface atthe first edge and a second contact surface at the second edge. Thefirst and the second contact surface may be at an outer corner, in alocked position of the first and the second panel, and may be in thejunction plane. The first and the second contact surface may beconfigured to cooperate.

The mechanical locking device may comprise a second space extending inthe junction plane from the first and the second contact surfaces and toan opening of the edge groove. The first and the second contact surfacesmay be configured to cooperate over a first width, in a direction froman inner corner to the outer corner of the first and the second panel,said first width may be in the range of about 5% to about 40%, about 5%to about 30%, or about 5% to about 20% of an edge width of a firstand/or second edge surface.

A first edge, surface and/or a second edge surface may comprise a recessextending from the first contact surface and the second contact surface,respectively, to the edge tongue and the edge groove, respectively.

The mechanical locking device may comprise a third contact surface atthe first edge and a fourth contact surface at the second edge. Thethird and the fourth contact surface may be at an inner corner in alocked position of the first and the second panel. The third and thefourth contact surface may be in the junction planer and are preferablyconfigured to cooperate.

The third and the fourth contact areas may be cooperating over a secondwidth, in a direction from an inner corner to the outer corner of thefirst and the second panel. Said second width may be in the range ofabout 2% to about 20%, about 2% to about 10%, or about 2% to about 5% ofan edge width of the first and/or second edge surface.

The first panel may comprise an inner half and an outer half in adirection of the thickness of the first panel. The entire edge tongue ispreferably at the inner half of the first panel.

The insertion groove may be parallel to the second main plane or at anacute angle to the second main plane, such that a bottom of theinsertion groove is at a greater distance from an inner face of thesecond panel than an opening of the insertion groove to the edge groove.

The insertion groove may extend along essentially the entire length ofthe edge groove.

The edge groove may extend long essentially the entire length of thesecond edge.

The flexible tongue may be displaceable ire the insertion groove.

A core material of the first and the second panel may comprise a woodfibre based board, such as a HDF, MDF, plywood, solid wood orparticleboard, or a reinforced plastic board or a wood fibre compositeboard. The core may be provided with a decorative layer.

The locking device may comprise a bevel or rounding at an opening of thetongue groove. This may facilitate disassembling as the bevel or therounding may prevent that the flexible tongue got stuck during thedisassembling.

The locking device is preferably configured such that the flexibletongue moves out of the tongue groove when a tool is inserted into thetongue groove and pushed back into the insertion groove.

The first panel and the second panel are preferably configured to beassembled by displacing the first panel relative the second panel in thesecond direction, wherein the first panel is perpendicular to the secondpanel. The edge tongue is inserted into the edge groove, wherein theflexible tongue is pushed back into the insertion groove and springsback into the tongue groove to obtain a locked position.

The flexible tongue may be according to the flexible tongue describedand shown in FIGS. 2A-2F or FIGS. 3A-3B in WO2015/105449. FIGS. 2A-2Fand FIGS. 3A-3B, and the accompanying disclosure at page 6, line 15 topage 7, line 15, are hereby expressly incorporated by reference herein.

The set of panels may be furniture panels.

A second aspect of the invention includes an assembled furniture productcomprising a corner of a frame comprising the set of panels as describedabove.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will by way of example be describedin more detail with reference to the appended schematic drawings, inwhich:

FIG. 1 shows an embodiment of the invention comprising the first paneland the second panel in a locked position.

FIG. 2 shows an enlargement of the encircled area in FIG. 1 without theflexible tongue.

FIGS. 3A-3B show an embodiment of the invention comprising the firstedge and the second edge.

FIGS. 4A-4F shows part of the invention comprising an embodiment of theflexible tongue.

DETAILED DESCRIPTION

FIG. 1 and FIG. 2 show an embodiment including a set of panelscomprising a first panel 2 with a first main plane and a second panel 4with a second main plane. The first and the if second panel are providedwith a mechanical locking device for locking a first edge of the firstpanel 2 to a second edge of the second panel 4 at a junction plane J.The first main plane is essentially perpendicular to the second mainplane and the junction plane is extending between the first main planeand the second main plane. The panels are shown in a locked position ina crosscut view. A longitudinal direction of the first and the secondedge are extending perpendicular to the view shown. The first edgecomprises an edge tongue 22 that extends from the junction plane J. Thesecond edge comprises an edge groove 21 at the junction plane, whereinthe edge tongue is configured to cooperate with the edge groove forlocking together the first and the second edges in a first direction D1which is perpendicular to the first main plane. The edge tongue 22comprises a tongue groove 10. The edge groove 21 comprises a flexibletongue 30 arranged in an insertion groove 20, said flexible tongue isconfigured to cooperate with the tongue groove 10 for locking togetherthe first and the second edges in a second direction D2 which isperpendicular to the second main plane. The mechanical locking devicecomprises a first space 46 between the edge tongue 22 and the edgegroove 21 at an opening of the edge groove 21 and at the junction planein a locked position of the first and the second edge. The first space46 may have the advantage that a loading of a part of the second edge atthe opening of the edge groove is avoided. This part of the second edgemay be a weak part, since little material is available to absorb a load.FIG. 2 shows an enlargement of the encircled area in FIG. 1 without theflexible tongue. The angle 74 between the junction plane and the firstmain plane may be in a range of about 30° to about 60°, for exampleabout 45°. The edge tongue 22 preferably extends, from the junctionplane, essentially in the second direction.

The first panel 2 has a first thickness 65 and the second panel 4 has asecond thickness 64. The first and the second thickness may beessentially the same. The first panel 2 comprises an inner half 66, at afirst side of a central plane 68 of the first panel, and an outer half67, at second side of the central plane 68 of the first panel, in adirection of the thickness of the first panel. The entire edge tongue 22is preferably at the inner half of the first panel. This may have theeffect that more material is obtained between the edge groove 21 and anouter corner, in a locked position of the first and the second panel,which may increase the strength of the mechanical locking device. Thefirst panel comprises an inner face 60 and an outer face 61. The secondpanel comprises an inner face 62 and an outer face 63.

FIG. 2 shows that first side of the edge tongue 22 may comprise, at ornear the junction plane J, a first locking surface 41, and the edgegroove 21 may comprises, at or near the junction plane J, a secondlocking surface 40. The first locking surface and the second lockingsurface are essentially parallel and are configured to cooperate forlocking in the first direction. The first locking surface and the secondlocking surface are preferably extending essentially in the seconddirection. The edge tongue 22 at a second side, which is opposite thefirst side, may comprise a third locking surface 43 and the edge groove21 may comprise a fourth locking surface 42, wherein the third lockingsurface and the fourth locking surface are essentially parallel and areconfigured to cooperate at a distance from the junction plane forlocking in the first direction. The third locking surface and the fourthlocking surface are preferably extending essentially in the seconddirection. The first, second, third and fourth locking surfaces may allbe parallel to each other. Said parallel first, second, third, andfourth locking surfaces may have the advantage that panels are easy toassemble and that, e.g., a furniture comprising said set of panels maybe more stable. The fourth locking surface 42 is preferably closer tothe central plane 68 than the second locking surface 40.

The third locking surface 43 and the fourth locking surface 42 maycooperate, to absorb a load, at an area extending over a first distance47 in the second direction. The third locking surface and the fourthlocking surface are preferably displaced from the junction plane by asecond distance 48. This may have the effect that more material isobtained, in the first direction D1, between the fourth locking surface42 and the junction plane, which may increase the strength of themechanical locking device. The first distance 47 may be within the rangeof about 20% to about 200% of the second distance 48 or within the rangeof about 50% to about 150% of the second distance 48. The first 47distance is essentially the same as the second distance 48 in theembodiment shown in FIG. 2.

The first side of the edge tongue 2, at a distance from the junctionplane, may comprise a fifth locking surface 45 and the edge groove 21may comprise a sixth locking surface 44 at a distance from the junctionplane J. The fifth locking surface and the sixth locking surface areessentially parallel and are preferably configured to cooperate forlocking in the first direction. The fifth locking surface and the sixthlocking surface are preferably extending essentially in the seconddirection. The insertion groove 20 is, in the embodiment shown FIG. 2,positioned between the sixth locking surface 44 and the second lockingsurface 40. The tongue groove 10 may be positioned between the fifthlocking surface 45 and the first locking surface 41.

FIG. 3A-3B show an embodiment of the mechanical locking device, beforeassembling of the first and the second panel, comprising a first contactsurface 51 at the first edge and a second contact surface 52 at thesecond edge. Said first and the second contact surface are at an outercorner, in an assembled and locked position of the first and the secondpanel, and in the junction plane, and are configured to cooperate. Asecond space 49 may extend in the junction plane from the first and thesecond contact surfaces 51,52 and to an opening of the edge groove, seeFIG. 2. The second space 49 may extend in a longitudinal direction alongthe first edge, along the second edge, or along both the first edge andthe second edge. The first and the second contact surfaces 51,52 maycooperate over first width 71, in a direction from an inner corner tothe outer corner of the first and the second panel, wherein said firstwidth is in the range of about 5% to about 40%, about 5% to about 30%,or about 5% to about 20% of an edge width 58 of a first and/or secondedge surface of the first and the second edge, respectively. This mayimprove the contact between the first edge surface and the second edgesurface, with increased pressure over smaller contacts areas, andirregularities, such as loose fibres that remains from a mechanicalcutting of the mechanical locking device, in the first edge surface orthe second edge surface are compressed and that a tight joint isobtained between the first and the second panel.

The first edge surface of the first edge may comprise a recess 55,indicated by a dotted line in FIG. 3B, extending from the first contactsurface 51 to the edge tongue 22. The second edge surface of the secondedge may comprise a recess 50, with a depth 76 and width 59, see FIG.3A, extending from the second contact surface 52 to the edge groove 21.The depth 76 of the recess 50 of the second edge surface may be about inthe range of about 0.1 mm to about 1 mm, preferably in the range ofabout 0.2 mm to about 0.5 mm. The recess 55 of the first edge surfacemay have the same depth and essentially the same length as the recess 50of the first edge surface. The depth of the recess may be adjusted tothe material of the core of the panel. Mechanical cutting of e.g. a coreof a particle board may result in a rougher surface with protrudingfibers than mechanical cutting of a core of a HDF board. A roughersurface may require an increased depth 76 of the recess of the firstedge surface and/or the second edge surface.

The mechanical locking device may comprise a third contact surface 53 atthe first edge and a fourth contact surface 54 at the second edge. Thethird and the fourth contact surfaces are at an inner corner, in alocked position of the first and the second panel, and in the junctionplane and are configured to cooperate. The third and the fourth contactsurfaces are cooperating over a second width 72, in a direction from aninner corner to the outer corner of the first and the second panel. Thesecond width 72 may be in the range of about 2% to about 20%, about 2%to about 10%, or about 2% to about 5% of the edge width 58 of the firstand/or second edge surface.

The first panel 2 and the second panel 4 are preferably configured to beassembled by displacing the first panel 2 relative the second panel 4 inthe second direction D2, wherein the first panel is perpendicular to thesecond panel. The edge tongue 22 is inserted into the edge groove 21,wherein the flexible tongue 30 is pushed back into the insertion grooveand springs back into the tongue groove 10 to obtain a locked position.The set of panels may be furniture panels.

The insertion groove 20 may extend along essentially the entire lengthof the edge groove.

The edge groove 21 may extend along essentially the entire length of thesecond edge in a longitudinal direction of the second edge.

The flexible tongue 30 may be displaceable in the insertion groove.

The locking device is preferably configured such that the flexibletongue 30 moves out of the tongue groove 10 when a tool is inserted intothe tongue groove and pushed back into the insertion groove.

The insertion groove 20 may be parallel to the second main plane or atan acute angle 75 to the second main plane, such that a bottom of theinsertion groove 20 is at a greater distance from an inner face 62 ofthe second panel than an opening of the insertion groove to the innerface 62.

The locking device may comprise a bevel or rounding at an opening of thetongue groove 10. This may facilitate disassembling as the bevel or therounding may prevent the flexible tongue from getting stuck during thedisassembling.

The set of panels as described above may be a part of an assembledfurniture product, such as a corner of a frame. The tongue groove 10 maybe open at a backside of the furniture, such that a tool may be insertedinto the tongue groove to push, back the flexible tongue 30 into theinsertion groove 20 and unlock the locking device.

A core material of the first and the second panel may comprise a woodfibre based board, such as a HDF, MDF, plywood, solid wood orparticleboard, or a reinforced plastic board or a wood fibre compositeboard. The core may be provided with a decorative layer or layers. Partsof the locking device may be formed, preferably by mechanical cutting,such as milling, of material of the first and the second panel.

An embodiment of the flexible tongue 33, which is displaceable in aninsertion groove 20, is shown in FIGS. 4A-4D. FIGS. 4A-4B show theflexible tongue 30 in a locked portion and FIGS. 4C-4D show the flexibletongue 30 during assembling of the first panel 2 and the second panel 4.FIG. 4B shows a cross section of the flexible tongue 30 in FIG. 4A. FIG.4D shows a cross section of the flexile tongue 30 in FIG. 4C. Theflexible tongue 30 comprises bendable protruding parts 24. A space 23 isprovided between the flexible tongue 30 and a bottom wall of theinsertion groove 20. FIG. 4C shows that the flexible tongue 30 is pushedinto the insertion groove 20 and towards the bottom wall of theinsertion groove 20 during an assembly of the first panel 2 with thesecond panel 4. The flexible tongue 30 springs back toward its initialposition when the first panel 2 and the second panel 4 have reached alocked position. A recess 25 is preferably arranged at each bendableprotruding part.

The flexible tongue 30 may have a first displacement surface 26 and anopposite second displacement surface 27, configured to be displacedalong a third displacement surface 28 and a fourth displacement lockingsurface 29, respectively, of the insertion groove 20.

An alternative embodiment of the flexible tongue 30, without theprotruding bendable parts 24, is shown in FIGS. 4E-4F. FIG. 4F shows across section of the flexible tongue 30 shown in FIG. 4E. Thealternative embodiment is bendable in its length direction in order toaccomplish a similar function as the embodiment shown in FIGS. 4A-4D.

When the word “about” is used in this specification in connection with anumerical value, is intended that the associated numerical value includea tolerance of ±10% around the stated numerical value.

EMBODIMENTS

1. A set of panels comprising a first panel (2) with, a first main planeand a second panel (4) with, a second main plane, wherein the firstpanel and the second panel are provided with a mechanical locking devicefor locking a first edge of the first panel (2) to a second edge of thesecond panel (4) at a junction plane (J), wherein the first main planeis essentially perpendicular to the second main plane and the junctionplane is extending between the first main plane and the second mainplane, characterized in that:

-   -   the first edge comprises an edge tongue (22) that extends beyond        the junction plane (J),    -   the second edge comprises an edge groove (21) at the junction        plane, wherein the edge tongue is configured to cooperate with        the edge groove for locking together the first and the second        edges in a first direction (D1) which is perpendicular to the        first main plane,    -   the edge tongue (22) comprises a tongue groove (10),    -   the edge groove (21) comprises a flexible tongue (30) arranged        insertion groove (20), said flexible tongue is configured to        cooperate with the tongue groove (10) for locking together the        first and the second edges in a second direction (D2) which is        perpendicular to the second main plane,    -   the mechanical locking device comprises a first space (46)        between the edge tongue (22) and the edge groove (21) at an        opening of the edge groove (21) and at the junction plane in a        locked position of the first and the second edge.

2. The set of panels as in embodiment 1, wherein the angle (74) betweenthe junction plane and the first main plane, is about 45°.

3. The set of panels as in embodiment 1 or 2 wherein edge tongue (22)extends, from the junction plane, essentially in the second direction.

4. The set of panels as in any one of the preceding embodiments, whereina first side of the edge, tongue (22) comprises, at or near the junctionplane (J), a first locking surface (41), and the edge groove (21)comprises, at or near the junction plane (J), a second locking surface(40), wherein the first locking surface and the second locking surfaceare essentially parallel and are configured to cooperate for locking inthe first direction, the first locking surface and the second lockingsurface are preferably extending essentially in the second direction.

5. The set of panels as in any one of the preceding embodiments, whereinthe edge tongue (22) at a second side, which is opposite the first side,comprises a third locking surface (43) and the edge groove (21)comprises a fourth locking surface (42), wherein the third lockingsurface and the fourth locking surface are essentially parallel and areconfigured to cooperate at a distance from the junction plane forlocking in the first direction, the third locking surface and the fourthlocking surface preferably extend essentially in the second direction.

6. The set of panels as in embodiment 5, wherein the third lockingsurface (43) and the fourth locking surface (42) cooperate at an areaextending over a first distance (47) in the second direction, whereinthe third locking surface and the fourth locking surface are displacedfrom the junction plane by a second distance (48), wherein the firstdistance (47) is within the range of about 20% to about 200% of thesecond distance (48) or within the range of about 50% to about 150% ofthe second distance (48).

7. The set of panels as in any one of the preceding embodiments, whereinthe first side of the edge tongue (22), at a distance from the junctionplane, comprises a fifth locking surface (45) and the edge groove (21)comprises a sixth locking surface (44) at a distance the junction plane(J), wherein the fifth locking surface and the sixth locking surface areessentially, parallel and are configured to cooperate for locking in thefirst direction the fifth locking surface and the sixth locking surfacepreferably extend essentially in the second direction.

8. The set of panels as in any one of the preceding embodiments, whereinthe mechanical locking device comprises a first contact surface (51) atthe first edge and a second contact surface (52) at the second edge, thefirst contact surface and the second contact surface are at an outercorner, in a locked position of the first and the second panel, and inthe junction plane and are configured to cooperate.

9. The set of panels as embodiment 8, wherein the mechanical lockingdevice comprises a second space (49) extending in the junction planefrom the first and the second contact surfaces (51,52) and to an openingof the edge groove.

10. The set of panels as in embodiment 8 or 9, wherein the first and thesecond contact surfaces (51,52) are cooperating over a first width (71),in a direction from an inner corner to the outer corner of the first andthe second panel, wherein said first width is in the range of about 5%to about 40%, about 5% to about 30%, or about 5% to about 20% of an edgewidth (58) of the first and/or second edge surface.

11. The set of panels as in any one of the embodiments 8-10, wherein thefirst edge surface and/or the second edge surface comprises a recess(50,55) extending from the first contact surface (51) and the secondcontact surface (52), respectively, to the edge tongue (22) and the edgegroove (21), respectively.

12. The set of panels as in any one of the preceding embodiments,wherein the mechanical locking device comprises a third contact surface(53) at the first edge and a fourth contact surface (54) at the secondedge, the third and the fourth contact surface are at an inner corner,in a locked position of the first and the second panel, and in thejunction plane, and are configured to cooperate.

13. The set of panels as in embodiment 12 wherein the third and thefourth contact areas are cooperating over a second width (72), in adirection from an inner corner to the outer corner of the first and thesecond panel, said second width may be in the range of about 2% to about20%, about 2% to about 10%, or about 2% to about 5% of an edge width(58) of the first and/or second edge surface.

14. The set of panels as in any one of the preceding embodiments,wherein the first panel comprises an inner half (66) and an outer half(67) in a direction of a thickness of the first panel, wherein theentire edge tongue (22) is at the inner half of the first panel.

The invention claimed is:
 1. A set of panels forming a corner jointhaving an inner corner joint portion and an outer corner joint portion,comprising a first panel with an outer surface defining a first mainplane and a second panel with an outer surface defining a second mainplane, wherein the first panel and the second panel are provided with amechanical locking device for locking a first edge of the first panel toa second edge of the second panel at a junction plane, and wherein thefirst main plane is essentially perpendicular to the second main planeand the junction plane is extending between the first main plane and thesecond main plane, wherein the first edge comprises an edge tongue thatextends beyond the junction plane, wherein the second edge comprises anedge groove at the junction plane, wherein the edge tongue is configuredto slidably engage with the edge groove for locking together the firstand the second edges in a first direction which is perpendicular to thefirst main plane, wherein the edge tongue has an inner corner portionfacing the inner corner joint portion and an outer corner portion facingthe outer corner joint portion, and the edge tongue comprises a tonguegroove on the inner corner portion of the edge tongue, wherein the edgegroove has an inner corner portion facing the inner corner joint portionand an outer corner portion facing the outer corner joint portion, andthe edge groove comprises a flexible tongue arranged in an insertiongroove on the inner corner portion of the edge groove, and said flexibletongue is configured to engage with the tongue groove for lockingtogether the first and the second edges in a second direction which isperpendicular to the second main plane when the first and second edgesare locked together, wherein the mechanical locking device comprises afirst space between the edge tongue and the edge groove at an opening ofthe edge groove and at the junction plane on the outer corner portion ofthe edge tongue in a locked position of the first and the second edge,wherein a first side of the edge tongue adjacent the tongue groovecomprises, at or near the junction plane, a first locking surface, and afirst side of the edge groove adjacent the insertion groove comprises,at or near the junction plane, a second locking surface, wherein thefirst locking surface and the second locking surface are essentiallyparallel and are configured to slidably engage for locking in the firstdirection when the first and second edges are locked together, whereinthe edge tongue at a second side adjacent the first space, which isopposite the first side, comprises a third locking surface and the edgegroove at a second side adjacent the first space comprises a fourthlocking surface, wherein the third locking surface and the fourthlocking surface are essentially parallel and are configured to slidablyengage at a distance from the junction plane for locking in the firstdirection when the first and second edges are locked together, andwherein the first locking surface and the third locking surface areessentially parallel.
 2. The set of panels as claimed in claim 1,wherein the angle between the junction plane and the first main plane isabout 45°.
 3. The set of panels as claimed in claim 1, wherein edgetongue extends, from the junction plane, essentially in the seconddirection.
 4. The set of panels as claimed in claim 1, wherein the thirdlocking surface and the fourth locking surface engage at an areaextending over a first distance in the second direction, wherein thethird locking surface and the fourth locking surface are displaced fromthe junction plane by a second distance, wherein the first distance iswithin the range of about 20% to about 200% of the second distance. 5.The set of panels as claimed in claim 1, wherein the first side of theedge tongue, at a distance from the junction plane, comprises a fifthlocking surface and the first side of the edge groove comprises a sixthlocking surface at a distance from the junction plane, wherein the fifthlocking surface and the sixth locking surface are essentially paralleland are configured to engage for locking in the first direction.
 6. Theset of panels as claimed in claim 1, wherein the mechanical lockingdevice comprises a first contact surface at the first edge and a secondcontact surface at the second edge, the first contact surface and thesecond contact surface are at an outer corner, in a locked position ofthe first and the second panel, and in the junction plane and areconfigured to engage.
 7. The set of panels as claimed in claim 6,wherein the mechanical locking device comprises a second space extendingin the junction plane from the first and the second contact surfaces andto an opening of the edge groove.
 8. The set of panels as claimed inclaim 6, wherein the first and the second contact surfaces are engagedover a first width, in a direction from an inner corner to the outercorner of the first and the second panel, wherein said first width is inthe range of about 5% to about 40% of an edge width of the first and/orsecond edge surface.
 9. The set of panels as claimed in claim 6, whereinthe first edge surface and/or the second edge surface comprises a recessextending from the first contact surface and the second contact surface,respectively, to the edge tongue and the edge groove, respectively. 10.The set of panels as claimed in claim 6, wherein the mechanical lockingdevice comprises a third contact surface at the first edge and a fourthcontact surface at the second edge, the third and the fourth contactsurface are at an inner corner, in a locked position of the first andthe second panel, and in the junction plane, and are configured toengage.
 11. The set of panels as claimed in claim 10, wherein the thirdand the fourth contact surfaces are engaged over a second width, in adirection from an inner corner to the outer corner of the first and thesecond panel, wherein said second width is in the range of about 2% toabout 20% of an edge width of the first and/or second edge surface. 12.The set of panels as claimed in claim 1, wherein the first panelcomprises an inner half and an outer half in a direction of a thicknessof the first panel, wherein the entire edge tongue is at the inner halfof the first panel.
 13. The set of panels as claimed in claim 1, whereinthe edge tongue includes an outermost surface which is closest to, andspaced from, an innermost surface of the edge groove when the first andsecond edges are locked together.